Having a concept of death, far from being a uniquely human feat, is a fairly common trait in the animal kingdomHaving a concept of death, far from being a uniquely human feat, is a fairly
When the Virginia opossum feels threatened, she plays dead. Lying on the ground, curled up into something resembling the foetal position, with her eyes and mouth open and her tongue hanging out, she stops responding to the world. Her body temperature drops. Her breathing and heart rate are severely reduced. Her tongue, usually pink, takes on a blueish hue. She urinates, defecates, and expels a putrid-smelling liquid from her anal glands. To all outward appearance, she is no different from a corpse.
In this deathly state, she waits. The opossum is aware of her surroundings, monitoring the present danger: a coyote in search of food. The canine, though, would rather feast on fresh meat than on some long-dead corpse, rotting and full of pathogens. And so the danger passes. Then the opossum springs back into action, unscathed and unfazed, and goes about the rest of her day. The trick worked.
Despite the persuasive performance of death, no one would assume that the opossum herself believes that she’s playing dead. Her behaviour is most likely automatic, and the opossum no more knows that she’s disguising as a corpse than a stick-insect knows that she looks like a stick. While this presupposition is probably right, it would nevertheless be wrong of us to assume that there’s nothing to learn about animals’ concept of death from the opossum’s display. In fact, her little show is one of the best pieces of evidence we have of how widely distributed in nature the concept of death is likely to be.
Humans have long thought of themselves as the only animal with a notion of mortality. Our concept of death is one of those characteristics, like culture, rationality, language or morality, that have traditionally been taken as definitional of the human species – setting us apart from the natural world and justifying our boundless use and exploitation of it. However, as I have argued elsewhere, the widespread notion that only humans can understand death stems from an overly complex view of this concept. The human concept of death is not necessarily the only concept of death.
Understanding death does not require grasping its inevitability or its unpredictability, nor does it require understanding that death applies to all living things or being familiar with its underlying physiological causes. In minimal terms, the concept of death is simply made up of two notions: non-functionality and irreversibility.
This means that all an animal needs to grasp in order for us to be able to credit her with some understanding of death is that dead individuals don’t do the sorts of things that living beings of her kind usually do (ie, non-functionality) and that this is a permanent state (ie, irreversibility). This minimal concept of death requires very little cognitive complexity and is likely to be very widespread in the animal kingdom.
The opossum’s death display, also known as thanatosis, is an excellent demonstration of this, not because of what it tells us about the opossum’s mind, but because of what it shows us about the minds of her predators: animals such as coyotes, racoons, dogs, foxes, raptors, bobcats and large snakes.
In the same way that the appearance of the stick insect tells us something about how her predators see the world, and which sorts of objects they avoid eating, the opossum’s thanatosis reveals how common the concept of death is likely to be among the animals that feed on her.